I just swapped a b20b into my friends 95 honda civic ex the motor starts up nice but after a few seconds the idle just drops really low and the car dies out. The motor is a stock b20b with a ls tranny, we are using an ls intake manifold and ls ecu, we are also using his stock ex engine harness. I cant figure out the problem so any help would be great

 

need help!!

 

I am having the same exact problem. I believe its the vacuum routing but I am not sure how to get it right. If anyone has any input on this I would greatly appreciate it.

 

well i am going to mess around with the vacuum lines ill let you know if i come up with anything

 

anyone know the vacuum diagram for the b20b?

 

still need help

 

are you throwing any codes?

 

check the little black purge valve on the back of the manifold, if thats hooked up backwards with the idle air control it will shut the car off, had the same problem, and just for the record a B20B with a LS ecu will make the motor run slightly lean. a FPR or a Vtec/AFC and +20 it and it will fatten it up a bit

 

thanks for the infor i will try that out right now and let you know how it goes

 

keep me posted bro.

 

your right about the ls ecu but on the car it warms up and once its warmed up it idles low and then dies out and if it doesnt die out it just stays idle and then it just drops suddenly then it jumps back up and drops again the idle basically bounces alot and it smells really rich in fuel too

 

might have something to do with the IACV itself, try unplugging it while the car is running and see if it makes a difference or not.

 

ok ill try that right now while the car is warm

 

the car stays on now but the idle just drops really low and then starts going back up slowly

 

another problem it keeps destroyng the intake air temp sensor